In an ultrasound diagnostic equipment, a delay line with more than one tap is used. Thus, a signal received by each transducer is supplied to the specified tap on the delay line to output the synthesized receive signal obtained by adding each signal having the respective specified delay time from one end of this delay line. Delay time of each signal is changed by delay-line tap selection to change the received wave beam direction and focus. Delay-line tap selection is made using a matrix switch to enable any one of the received signals to connect to any one of the taps.
As aforementioned, the matrix switch becomes the principal part of the ultrasound diagnostic equipment. On the other hand, the matrix switch is provided with several thousand switching elements.
So far, this matrix switch has been checked by means of a complex checking device as disclosed in Japanese Patent Provisional Publication No. 44364/82. Thus, the matrix switch has been checked only by the use of a special checking device.